An electrical switch of the kind concerned typically has a casing, two fixed contacts, and a moving contact which is resiliently biased towards contacting the fixed contacts, whereby the switch is closed. A spring-loaded actuator is used to bring about movement of the moving contact relative to the fixed contacts, and in particular to move the moving contact out of contact from the fixed contacts for opening the switch.
During opening of the switch, it is unpredictable as to which one of the fixed contacts the moving contact is to leave last. This is a concern in the design of heavy-current switches as arcing and/or flashover often occur at where the circuit is opened i.e. across the moving contact and the fixed contact it departs last. Of course, both fixed contacts together with the moving contact can be enhanced for better performance, for example made larger and/or coated with platinum, but production cost will escalate. Another consideration is the speed at which the moving contact is separated from the fixed contacts.
The invention seeks to provide an improved electrical switch of this type in general.